The present invention relates to dental treatment appliances, and more particularly to ultrasound appliances, such as scaling appliances, surfacing appliances (for eliminating biofilms), or cutting appliances (cavities or preparations for a prosthesis), all comprising instruments that vibrate at ultrasound frequencies.
FIG. 1 shows an ultrasound treatment appliance 100 that comprises an ultrasound generator 110 connected to a handpiece 120 via a cord 111. A sonotrode or ultrasound tip 130 is mounted at the end of the handpiece 120. In well-known manner, the handpiece 120 includes a transducer (not shown) e.g. made of piezoelectric material, and coupled mechanically to the tip 130 in such a manner as to transmit vibratory waves thereto at an amplitude that is determined as a function of the power delivered by the ultrasound generator 110.
The tip is an interchangeable part that presents a wide variety of shapes depending on the treatment for which it is intended. Examples of such tips are described in particular in U.S. Pat. Nos. 6,312,256 and 4,283,175. The amplitude or the power of the ultrasound waves transmitted by the generator also depends on the type of treatment that is to be applied. For example, for periodontal debridement, the required power/amplitude is much less than that required for removing scale. In addition, the type of tip used may differ as a function of the treatment to be performed. Consequently, for each type of dental treatment, there exist one or more families of tips that are for operating with ultrasound waves in respective determined power and amplitude ranges.
Consequently, dental treatment appliances include an ultrasound generator of power that can be adjusted as a function of the treatment being performed and/or of the tip in use. In order to make such appliances easier for practitioners to use, ultrasound generators are fitted with buttons or keys 113 to 116, for example, that make it possible automatically to select a power range that is appropriate for the treatment. These keys are identified by a color code or the equivalent enabling the practitioner to select the appropriate power range, and once selected, the range can be specified on a screen 112.
Nevertheless, as explained above, specific tips are also used for each treatment that are themselves intended to operate in one of the power ranges preadjusted on the appliance. Consequently, the practitioner must also verify that the tip placed on the handpiece is well adapted to the selected power range, or conversely must select the power range that corresponds to the tip mounted on the handpiece.
For this purpose, one of the known solutions consists in packaging each tip on a distinctive support element. The support element carries marking that matches that of the power range selection keys. For example, if the keys are identified by a color code, each support presents a color code corresponding to that of the key used for selecting the best power range for the tip placed on the support.
Another solution consists in marking the tip directly with a color code or the like enabling the practitioner to identify the power range for using the tip. This type of tip marking is described in French patent document FR 04/06630.
Nevertheless, whatever the identification technique used, selecting the power range on the ultrasound generator requires intervention on the part of the practitioner, thereby complicating the use of the dental treatment appliance for the practitioner, and not eliminating the risk that the wrong power range might be selected on the generator.
U.S. Pat. No. 6,503,081 describes an ultrasound appliance comprising a handpiece fitted with a magnetostrictive element connected to an ultrasound generator. The ultrasound generator has processor means programmed to apply a series of signals of varying frequency to the magnetostrictive element of the handpiece carrying a tip and to measure the consumption of the magnetostrictive element in order to detect the frequency that corresponds to the resonant frequency of the handpiece fitted with the tip. Thereafter the processor means adjust the generator to said detected resonant frequency. However, although that document discloses a solution for detecting and adjusting the ultrasound generator on the resonant frequency of the tip mounted on the handpiece, it does not enable the type of tip mounted on the handpiece to be identified. Without the tip being recognized specifically, it is not possible to adjust the generator on a power and amplitude range that is adapted to the type of tip mounted on the handpiece.